In recent years, with the development of techniques, especially the rapid development of mobile communication techniques, more and more mobile electronic devices appear in people's life. For example, smart phones, tablet PC, laptops and multi-functional media player have become necessities in people's daily life. In these mobile electronic devices, a voice player is an essential component, and voice quality of the voice player can directly influence experience of a user when using these mobile electronic devices.
A miniature speaker is used as the voice player, and a structure of the miniature speaker directly influences the voice quality. In the relevant art, the miniature speaker includes a frame, a voice diaphragm, a voice coil, a diaphragm and a flexible circuit board. The voice coil is located below the voice diaphragm and is configured to drive the voice diaphragm to vibrate and sound. The diaphragm is configured to elastically support the voice coil. The flexible circuit board is located below the voice coil and is fixedly connected with the voice coil, so as to connect the voice coil with an external circuit. The diaphragm is fixed connected below the flexible circuit board. The diaphragm includes a first connecting portion, a second connecting portion and a suspension. The first connecting portion is fixedly connected with the frame, the second connecting portion is fixed connected with the voice diaphragm, and the suspension connects the first connecting portion with the second connecting portion. Additionally, the miniature speaker further includes a lower clamping plate located at a lower end of the frame, the suspension is a downward recessed structure recessed toward the lower clamping plate, and an airflow channel is defined between the diaphragm and the lower clamping plate. The voice coil vibrates to generate air flow, and the air flow flows out through a leaking hole in the frame. When the suspension is the downward recessed structure recessed toward the lower clamping plate, the suspension will occupy space of the airflow channel. As a result, the air flow cannot be smoothly discharged and thus the air inside the miniature speaker cannot flow smoothly, and the heat radiation of the miniature speaker is reduced accordingly. Additionally, when the miniature speaker is made into a speaker box, a sound absorbing material will be filled in a rear cavity of the speaker box. Since the air in the speaker cannot flow smoothly, the sound absorbing material cannot effectively improve a low frequency performance of the speaker.